The Art of NO
That is right, I'm talking about getting into that situation where you didn't say no (when you should of, but you was just being friendly or trying to keep the Peace) to a member and now they are running circles around you. Early in being a mod/admin/owner you learn that life lesson of not being to nice. There will always be them members who ask for an inch and take a mile, then you will have to give the mile to every other player/member in fear of it seeming like favouritism. Its a mistake I've done many time over the years.
The hard part is to be firm but not alienate yourself from the rest of the players. The best way to do it is to be firm BUT fair right from the get go, don't let yourself become a soft apple. Don't take this in the sense that you need to become this stone cold mother....you get what I mean. Just realise that you need to put on your admin/owner/moderator hat on and deal with people that way. Not in the way you would deal with a friend.
All members/Mod and Admins all know when it comes down to the community issues, I am talking as a owner. No your Internet friend or even your personal friend.
Lets say one of the members from our Minecraft server asks me if they can set a warp.(being able to set a teleport for you non minecrafter's) Well on our minecraft server we don't allow normal non donating members to have that ability. I would tell them no, the reason why I said no and any other information which would be helpful to that member at the time.
It would go down something like this.
Member : Can i have a warp set please
Me: No sorry we don't allow [member] ranked players to be able to set a warp. This is because we don't wish to have 100's of warps on the server and want people to actually move around and see the whole map. However [VIP] rank has the ability to set 1 public warp, to get [VIP] you can either donate money or donate some of your time to basic jobs that we need help with.
Never just say "No" always back it up with reason. It will make the player understand that you are not just being mean. That's the reason you are saying "No" is because of this reason and you are not treating them any different to any other member/player.
Learn from an old hand, don't say yes when inside you mean no.